Container closure



Jan. 10, 1967 P. P. STEVENS, JR

CONTAINER CLOSURE Filed Dec. 5, 1964 2 Sheets-Sheet 1 3/ T I" [/1 I/CPWLI I) I I. I I I E] A 26 27: l /6 35 24 I l3 INVENTOR. PE TE? 1? 5 TE vErvs JR ATTORNEY 1967 P. P. STEVENS, JR 3,297,193

CONTAINER CLOSURE 2 Sheets-Sheet 2 Filed Dec. 5, 1964 INVENTOR. PETER P. STEVENS JR ATTORNEY United States Patent 3,297,193 CONTAINER CLOSURE Peter P. Stevens, Jr., Point Reyes Station, Calif., asslgnor to Walter Lander, San Francisco, Calif. Filed Dec. 3, 1964, Ser. No. 415,648 12 Claims. (Cl. 220-60) The present invention relates generally to closures for containers and, more particularly, to a cap or lid that can be rigidly secured or latched over a container body mouth to provide a normally non-removable closure yet is made of a relatively elastic or resilient material. Caps or lids formed of resilient or elastic plastic, such as polyethylene or polypropylene, are commonly employed as closure for container bodies. However, the natural resiliency of such materials has heretofore offered a problem in the use of such caps for tightly forming a normally permanent closure on a container which is relatively nonremovable much like the metal lid of a can-type container.

Due to the low cost of resilient plastic material, such as polyethylene or polypropylene, a lid formed thereof which provides a relatively non-removable closure on the container is highly desirable. This is especially true with respect to widely used paperboard containers, because such a lid can render paperboard suitable for use in making permanently sealed containers.

Summarizing this invention, it overcomes the aforementioned problem encountered with caps or lids of relatively resilient or elastic material in providing a more or less permanent closure on a container body, in contradistinctiton to a closure arrangement in which the cap is designed for replacement over the container mouth after removal thereof. Relatively stifi elastic plastic material, such as high density polyethylene or polypropylene, is advantageous for use in the cap of the invention hereof especially when such cap is employed in combination with paperboard containers because such a cap when secured to the container in the manner hereinafter described, provides a one-use container or paperboard can analogous to a seamed can-type container. Although the closure hereof has found particular applicability with such plastic lids and paperboard containers, it can be employed in any arrangement where the lid is of a relatively stiff elastic material capable of restoration to its original shape after flexing, and with other container bodies besides paperboard.

In general, the invention comprises a closure arrangement in which a cap or cover of relatively stiff elastic material has a ridge which dogs wit-h a shoulder about a container body mouth. That is, the cap ridge and container body shoulder have surfaces which interlock or latch so that camming action between them is prevented if an attempt is made to remove the cap. In addition, the surfaces of the cap and cover at the closure arrangement are arranged to be in tight engagement. This tight engagement and dogging of the cap ridge and container body latching surfaces provide the non-removable tight seal of the present invention.

For ease in construction, the shoulder on the container body is desirably formed by folding the side wall of the container body upon itself. In this manner, a skirt is formed extending from the container top edge at the mouth adjacent the surface of the side wall and terminating in a shoulder having a latching surface. Desirably, such shoulder is provided about the inner periphery of the container body month by inwardly folding the side wall upon itself; and the cap ridge latching surface engages such shoulder latching surface within the container body. With such construction, the latching arrangement is inside the container and cannot be tampered with from the ice exterior of the container without destruction of the container body or cap.

From the preceding, it is seen that the invention has as objects, among others, the provision of an improved non-removable and tight sealing closure arrangement for containers utilizing a relatively stiff elastic or flexible cap; an improved cap or lid of stiff elastic material, desirably plastic, for such a closure arrangement which can be easily and permanently secured to a container body and which forms a tight seal with the container body; and in which such closure arrangement is of simple and economical construction that can be easily made. Other objects and advantages of the invention will become apparent from the following more detailed description taken in conjunction with the attached drawings in which: FIGURE 1 is an isometric view of a cap of the invention constructed for latching in the interior of a container body and with a portion thereof cut away to illustrate its construction;

FIGURE 2 is an isometric sectional exploded view of the cap of FIGURE 1 and a portion of a container body, with a capper partly illustrated, in a position to apply the cap onto the container body;

FIGURE 2a is an isometric fragmentary sectional view of a container body showing a modification of the structure of FIGURE 2;

FIGURE 3 is an isometric sectional view of the capper, cap and container body of FIGURE 2, in which the capper is shown applying the cap onto the container body;

FIGURE 4 is an isometric view of the cap of FIGURE 1 sealed over a container body mouth with portions of the structure broken away to illustrate the construction more clearly;

FIGURE 5 is a vertical sectional view of another embodiment of an interior-latching cap of the invention, together with a partial view of a container body;

FIGURE 6 is an isometric view of an exterior-latching cap of the invention over the mouth of a container body with portions of the cap and container body cut away to illustrate their construction;

FIGURE 7 is an exploded isometric sectional view of the cap and container body of FIGURE 6 and a capper partly illustrated in a position to apply the cap onto the container body; and

FIGURE 8 is a view similar to that of FIGURE 7 showing the capper applying the cap onto the container body.

FIGURES 1 through 4 illustrate an interior-latching closure arrangement including a cap 11 of suitable impervious resilient or elastic material which is relatively stiff, such as polypropylene or high density polyethylene, and which can be slightly flexed but after flexing will restore itself to its original shape. The cap 11 comprises a top wall 12 adapted to overlie the mouth 13 and engage top edge 14 of a cylindrical container body 15. Such body 15 can be of any suitable material, but as stated before, is desirably paperboard. An integral annular flange 16 depends from top wall 12 of the cap and has an outside diameter such that it can fit tightly flush in en-- gagement wit-h a skirt 17 extending downwardly from top edge 14 of the container adjacent the inner surface 18 of the container side wall 19. The outside diameter of flange 16 is substantially equal to, or slightly greater than (in the order of .005 inch), the inside diameter of flange 16 to assure such tight fit. As will be explained hereinafter, this mating of flange 16 and skirt 17 cooperates in providing a tight seal between the cap and container.

Skirt 17 is desirably formed within body 15 by inwardly folding a top portion of container body 15 upon itself along a hinge connection which forms top edge 14 of the container body. As shown in FIGURE 2,

3 notches 21 are provided in skirt 17 in order to facilitate folding of the skirt so that it can easily lie flush against inner surface 18 of container side wall 19. However, the skirt can be a separate ring adhesively bonded to the inner surface of the container body.

A shoulder 22 at the bottom of skirt 17 provides a planar surface 23 extending laterally outwardly with respect to side wall 19 at substantially a right angle with reference to the axis or center line of the container, indicated by broken line 25. Flange 16 of the cap has an integral annular ridge 24 projecting outwardly from the outer periphery thereof, which has a planar surface 26 for engaging flush against shoulder surface 23 in faceto-face contacting relationship when the cap is tightly positioned or sealed on the container body. The distance of surfaces 23 and 26 from top edge 14 of the container is such, as will be explained more fully later, and the angles of surfaces 23 and 26 with reference to axis 25 are such that these surfaces interlock or, in other words, positively dog shoulder 22 and ridge 24 firmly together.

More particularly, any force component tending to remove cap 11 will generally be in the same direciton as axis 25, and the angles of engaging surfaces 23 and 26 (substantially right angles to the container axis 25 in the embodiment illustrated) are such as to form noncamming or dogging angles in the sense that a force exerted in an attempt to remove the cap does not result in a camming action between engaged surfaces 23 and 26.

Such angles of surfaces 23 and 26 provide hooking or dogging angles, and need not be right angles to axis 25 in order to provide such hooking or dog-ging. For example, as illustrated in FIGURE 21:, shoulder 22 can be undercut to form a non-camming surface which makes an angle less than 90 to axis 25 sloping upwardly toward the top of the container from its inner end or, in other words, forms a re-entrant angle with respect to the container top; and the dogging surface 26 on ridge 24 can be of a complementary angle.

Although it is desirable to have the angle of interlocking surfaces 23 and 26 not greater than 90 as explained above to insure non-camming action of these surfaces upon application of a force to remove the container cap, such angles may be slightly greater, in the order of 2 or 3, and the surfaces still will not earn. However, when such angles are excessively over 90, and an attempt is made to remove the cap, camming action between the surfaces results, and it is possible to remove the cap.

The periphery of the upper surface of cap top wall 12 has an annular ridge 27 thereabout. The remainder of such top wall upper surface thereby comprises a recessed portion 27'. An outer annular flange 28 depends from the periphery of ridge 27 and is adapted to engage the outer surface 29 of container body side Wall 19 about mouth 13. Such flange 28 is relatively short so that it does not interfere with the locking of the cap onto a container.

An open bottomed groove 31 is thus formed between spaced flanges 16 and 28 of a width for gripping skirt 1 7 and container side wall 19 in a tight sliding fit, with flange 16 in tight flush engagement with skirt 17, and flange 28 in tight flush engagement with side wall 19; and the top of groove 31 is closed by an unders-urface portion 31' which engages edge 14 of container mouth 13 in the closed position of the cap.

The distance between latching surface 26 of cap ridge Z4 and undersurface portion 31', denoted dimension A, is such compared to the distance between top edge 14 and latching surface 23 of the container body, denoted dimension B, as to effect tight dogging engagement between such latching surfaces when cap 11 is snap-docked or sealed on container body 15. Desirably, dimensions A and B are substantially equal and in such circumstances, the natural elasticity of the material results in placing :ensile stress on the flange of the cap with surface 26 4 of ridge 24 lying flush against surface 23 of shoulder 22.

Outer surface 30 of flange 16 has a configuration which is complementary to the side surface configuration of skirt 17. Thus, the above tight fit, besides assuring that cap 11 is non-removably latched onto body 15, causes outer surface 30 and undersurface portion 31 of cap 11 to tightly engage skirt 17 and edge 14, respectively, of container body 15 to provide a seal between such cap 11 and body 15. In other words, flange 16 is stressed in tight flush engagement with, or stretched over, skirt 17. Dimension A need not be exactly equal to dimension B as along as these dimensions are substantially equal. For example, dimension A can be less than dimension Bin the order of about 0.001 to 0.002 inchin order to provide such stressed tension on the cap. In any event, dimension A should not exceed dimension B to the extent that a tight snap-lock is not obtained; and dimension A should not be less than dimension B to the extent that snap-locking between surfaces 23 and 26 does not occur.

Undersurface portion 31' of top wall 12 is desirably above the plane through the center of recessed portion. 27' of top wall 12 inwardly of annular flange 16. T herefore, such recessed portion 27' bears against flange 16 and serves as a stiffening wall to maintain the uppermost por tion of flange 16 against skirt 17. Thus, recessed portions 27 cooperates in providing the tight seal and the nonremovable latching features of the present invention.

The following is an example of a container incorporating the closure arrangement of the invention. The container body is of 0.027 inch thick or caliper paperboard and has a height of 3.5 inches and an inner diameter of 2.690 inches. Skirt 17 extends 0.280 inch from top edge 14 along the inner surface 18 of the container body (dimension A). Due to the thickness of the skirt, the inner diameter of the container at the skirt is reduced to 2.635 inches.

The cap is of high density polyethylene with top wall 12 thereof 0.040 inch thick and an overall outside diameter of 2.840 inches. The outside diameter of flange 16 is 2.64 inches, which is slightly greater than the inside diameter of the container body at skirt 17 in order to provide a tight fit therebetween. Groove 31 is 0.054 inch wide, twice the caliper of the paperboard. The distance of undersurface portion 31' from latching surface 26 (dimension B) is 0.280 inch, the same as dimension A, and flange 28 is 0.125 inch long. It has been found that a container body and cap of the above materials, and a closure arrangement of the above dimensions provides a tightly sealed and normally permanently closed container.

As previously related, the cap is desirably formed of plastic, such as polypropylene or high density polyethylene, which is relatively stiff but yet sufliciently elastic or resilient to enable the cap to be snap-locked onto the container body. In this connection, the cooperable dogging parts on the cap and container body have such close dimensional relationship that the cap can only be placed onto the container body forceably through a flexing action applied to the cap. The force necessary to cause the flexing of the container cap to dog it onto the container body is so great because of the close dimensoinal relationship of the dogging parts that it is extremely diflicult or impossible to force the cap onto the container body without the employment of an outside instrumentality. In other words, it cannot be snapped onto the container body merely by hand.

However, the snap-locking of the container cap onto the container body can be easily accomplished by employing an outside instrumentality. For this purpose, a conventional capping machine (not shown) is employed which is provided Witha capper ring 32 on the capping part of the machine. The container body is supported in an upright position on the capping machine and cap 11 is placed on such body with flange 16 extending downwardly and ridge 24 engaging top edge 14. To facilitate insertion of flange 16 into mouth 13, latching ridge 24 is beveled on its bottom under the latching surface to provide an inwardly slanting camming surface 33 where it engages top edge 14 to center the cap properly on'the container mouth and to provide a camming face facilitating inward flexing of flange 16 and sliding movement of the cap onto the container when pressure is applied on capper ring 32 to effect full snap-locking or latching of the cap. Such capper ring 32 is brought into engagement with the exterior of cap 11 about the periphery thereof inward of flange 16, and pressure applied thereto to flex flange 16 so that it is forced onto the container mouth.

Capper ring 32 is moved sufficiently downwardly to effect snap-lock engagement of surface 26 on ridge 24 with surface 23 of shoulder 22. Because dimension A is substantially equal to and not substantially in excess of dimension B, ridge 27 about the periphery of cap top wall 12 will be simultaneously somewhat distorted by the container mouth edge 14, as shown in FIGURE 3, to allow engagement of dogging surfaces 23 and 26. However, when pressure is relieved from capper ring 32, the cap springs back to form the non-removable snap-lock latch and tight seal of this invention.

Since the latching surfaces are on the interior of the container, they cannot be tampered with from outside the container. Therefore, unless special structure is provided for removing the cap, the cap is non-removably locked onto the container. To have access to the contents of the container without such special structure, the cap or container body must be mutilated such as with a can opener. Or, if the container is to be used to package a pourable product such as salt or the like, conventional dispensing apparatus such as found on salt boxes can be provided in the top wall of the cap or side wall of the container body.

Another embodiment of an interior-latching cap is illustrated in FIGURE 5 and includes a pull tab structure which enables the top to be removed for access to the container contents. This embodiment is similar to the embodiment of FIGURES 1 through 4 and like parts are referred to by like numerals. However, in this embodiment, flange 16 is provided with spaced apart notches 35, the upper edges 35 of which extend to a position above ridge 24. In this manner, ridge 24 is segmented, i.e., made of a plurality of shorter ridges spaced about the outer periphery of flange 16. It has been found that such segmentation allows ridge 24 to more easily pass by skirt 17 into the container body, and thus facilitates sealing of the cap onto the container.

Top wall 12 of the cap of FIGURE 5 is planar, i.e., it does not have a ridge such as ridge 27 around the periphery of the upper surface thereof. Thus, it can be seen that while desirable, it is not necessary to have a recessed portion 27 such as in the previously described embodiment to enhance holding of cap flange 16 against container skirt 17.

In this embodiment, a plurality of reinforcing ribs or webs 34 connect top wall 12 of can 11 with flange 16 to hold such flange against skirt 17. These webs 34 thereby aid in positively maintaining flange 16 in mating relationship with skirt 17 to provide a tight seal. and surfaces 26 of ridge 24 against surface 23 of shoulder 22 to provide the interlock. If it is desired to be able to remove can 11, a projecting tab 36 is provided integral with ton wall 12 over one of the webs 34, as shown. Whenever this tab is pulled upward, it will cause the portion of cap top wall 12 beneath it to bow upward. The web beneath the tab and connected to such top wall portion will then coact with the tab to pull the bottom portion of flange 16 inward toward the center of the container and thus pull the portion of cap ridge 24 near such web from its latching position beneath container shoulder 22. Once a portion of such ridge has been disengaged from shoulder 6 22, the remainder of it can also be disengaged. This is especially true because ridge 24 is segmented. There is less surface engagement between such ridge and shoulder 22 than there would be if ridge 24 Were continuous.

Once the cap has been removed, it cannot be easily tightly sealed on container body 15 again with the latching surfaces in engagement without the employment of an outside instrumentality. The close dimensional relationship of the parts discussed previously makes hand application of the cap exceedingly diflicult.

If the ability to remove cap 11 is not desired, tab 36 is not provided. Webs 34 still perform their independent function of helping to maintain flange 16 against skirt 17. Further, while desirable for the reasons stated, ridge 24 does not have to be segmented in this embodiment. In addition, top wall 12 can be provided with a ridge and recessed portion similar to ridge 27 and recessed portion 27 of the cap illustrated in FIGURES 1 through 4.

Each of the features of this cap, i.e., the web and tab combination, the web alone, the planer top wall, and the segmented ridge, can be individually provided in the cap of FIGURES 1 through 4.

The invention is also applicable to a latching closure arrangement on the exterior of a container; although an exterior latching arrangement is not as advantageous as the foregoing described interior latching arrangement, because of the previously mentioned tamper-proof feature of the interior locking cap. In FIGURES 6 through 8 illustrating such exterior latching arrangement, a container body 15 is provided with a skirt 37 formed by outwardly folding side wall 19 upon itself. In this manner, a shoulder 38 is provided exteriorly of the container body having a surface 39 at a right angle with respect to outer surface 29 of container side wall 19. A ridge 41 on the latching cap 42 is on an outer flange 43 and extends laterally inwardly to form a latching surface 44, As in the case of the interior-latching cap, ridge surface 44 engages shoulder surface 39 in dogging, face-to-face relationship. In addition, dimension A-which is the distancebetween undersurface portion 46 of top wall 12 and ridge surface 44is as short as or slightly shorter than dimension B-which is the distance between mouth edge 14 and shoulder surface 29 of the container body. Flange 43 has an annular protuberance or ridge 45 on its inner surface which bites into the paperboard container body to further assure a tight seal between the cap and body.

An inner peripheral flange 47 depends from top wall 12' of the cap and lies flush in engagement with the inner surface of side wall 19. Desirably, undersurface portion.

46 of top wall 12 which engages edge 14 of mouth 13 is above the plane through thecenter of recessed Portion 27' of top wall 12 inwardly of flange 47'. Therefore, in the manner discussed with respect to-the interior-latching arrangement, the top wall maintains the uppermost portion of flange 47 against the inner surface 18 of side wall 19 to aid in providing a tight seal. Flange 47 also has an annular protuberance 45 to bite into the container to assure the tight seal. Thus, besides a tight seal being pro-- vided between outer flange 43 on the cap and skirt 37, a tight seal is provided between Wall 19 and inner flange 47. To further assure a tight seal between inner flange 47 and the container side wall, webs (not shown) similar to webs 34 on the interior-latching cap or FIGURE 5 can be provided between top wall 12 of the cap and flange 47.

To facilitate capping, the exterior surface of outer flange 43 is provided with scallops 48'terminating in lower abutments or ledges 49 generally parallel to top wall 12 of the cap. The capping of this embodiment is the same as that of the interior-latching arrangement except for changes necessitated by the exterior-latching feature. To place the cap onto the container body, capper ring 51 having fingers 52 is brought into engagement with the cap, with fingers 52 engaging ledges 49 to force the cap onto the body as shown in FIGURE 8. Rather than scallops the inner surface of side- 48 and ledges 49, a continuous ridge can be provided about the exterior surface of flange 43 to provide a surface for capper fingers 52 to engage.

As also shown in FIGURE 8, fingers 52 of ring 51 spread apart somewhat as they apply the cap onto the container body in order to allow ridge 41 to pass over skirt. 39. Ridge 41 also has a beveled or camming surface portion 33 to facilitate the application of cap 11 onto the body.

As can be seen from the above, the material of both the interior and exterior latching caps of the invention must be elastic or resilient enough to allow the latching ridges 24 and 41, respectively, to pass by the container body skirts 17 and 37 and latch therebeneath, but stiff enough to prevent the cap latching ridge from being deformed enough to allow disengagement from the body latching shoulders when a force tends to remove the caps. As stated before, high density polyethylene or polypropylene have been found to be particularly advantageous materials for such caps. For example, the polyethylene sold under the trademark Tenite with the designation 3460A by Eastman Chemical Products, Inc., of Kingsport, Tennessee, has a density 0.96% of crystalline density and has been found suitable for use in producing the cap of the invention. The polypropylene sold under the same trademark by the same company with the designation 4250 has a density 0.91% of crystalline density and is also suitable for producing such cap.

While the caps of the invention are particularly advantageously used in a closure arrangement with a paperboard container, they can also be used with container bodies made from other materials such as metal, plastic or glass. Also, the invention is applicable to many differently shaped container bodies and caps, as long as such different bodies and caps have latching surfaces that interlock so that camming action between them is prevented. In addition, the closure arrangement can be utilized on both ends of a container body. A cap of the invention can be applied to one end of the container body, the body filled with desired contents and, thereafter, another cap of the invention applied to the other end or mouth of such body.

I claim:

1. A sealing cap for a flexible container body of paperboard or the like which has a top edge about its mouth, and an integrally downwardly folded skirt of uniform thickness throughout hingedly depending from said top edge alongside the side wall of said container body and terminating in a shoulder having a latching surface extending laterally with respect to said side wall; said cap being of relatively stiff elastic plastic material capable of restoration to its original shape after flexing thereof and comprising a top wall for overlying said mouth and for engaging said top edge, a pair of spaced flanges depending from said top wall adjacent the periphery thereof which with an undersurface portion of said top wall therebetween define an open bottom groove for gripping the side wall and the skirt of said container body at said mouth with a first of said flanges in tight flush engagement with said side wall, and a second of said flanges in tight flush engagement with said skirt, and a ridge projecting laterally from said second flange and having a latching surface for dogging engagement with said latching surface of said skirt, the distance between said latching surface on said cap and said cap undersurface portion being such compared to the distance between said body top edge and said container body latching surface as to effect tight dogging engagement between said body and cap latching surfaces when said cap is sealed on said body and said top wall undersurface portion engages said body top edge.

2. A sealing cap for a flexible container body of paperboard or the like which has a top edge about its mouth, and an integrally downwardly folded skirt of uniform thickness throughout hingedly extending from said top edge along the inner surface of said body and terminating in a shoulder having a latching surface extending laterally with respect to said inner surface; said cap being of relatively stiff elastic material capable of restoration to its original shape after flexing thereof and comprising a top wall for overlying said mouth and for engaging said top edge, a flange depending from said top wall having an outer side configuration substantially complementary to the side surface configuration of said skirt for flush engagement with said skirt surface, and a ridge projecting laterally outward from said flange and having a latching surface for dogging engagement with said latching surface of said container body, the distance between said latching surface on said cap and an undersurface portion of said top wall adapted to engage said body top edge being such compared to the distance between said top edge and said container body latching surface as to effect tight dogging engagement between said body and cap latching surfaces when said cap is sealed on said body and said undersurface portion engages said body top edge, the bottom of said ridge under the latching surface thereof having a slanting camming surface to facilitate insertion of the cap flange into the container body upon application of pressure to the cap when it is being applied to the container body.

3. The sealing cap of claim 2 wherein a reinforcing web is provided between the top wall of said cap and said flange for maintaining said flange against said container body skirt.

4. The sealing cap of claim 3 wherein a pull tab is provided on the upper surface of said top wall over said web to coact with said web for disengaging said latching surfaces when said tab is pulled upward.

5. A sealing cap for a flexible container body of paperboard or the like which has a top edge about its mouth, and an integrally downwardly folded skirt of uniform .thickness throughout adjacent a side wall of said body hingedly connected to said top edge and terminating in a shoulder having a latching surface extending laterally with respect to said side wall, said cap being of relatively stiff elastic material capable of restoration to its original shape after flexing thereof and comprising a top wall for overlying said mouth and for engaging said top edge, a pair of spaced flanges depending from said top wall adjacent the periphery thereof which with an undersurface portion of said top wall therebetween define an open bottom groove for gripping the side wall and the skirt of said container body at said mouth with a first of said flanges in tight flush engagement with said side wall and a second of said flanges in tight flush engagement with said skirt, said second flange being longer than said first flange, and a ridge projecting laterally from said second flange and having a latching surface for dogging engagement with said latching surface of said skirt and being beveled to provide a camming surface to facilitate passage of said ridge past the top edge and skirt of said body when said cap is being applied on said container body, the distance between said latching surface on said cap and said cap undersurface portion being such compared to the distance between said body top edge and said container body latching surface as to effect tight dogging engagement between said body and cap latching surfaces when said cap is sealed on said body andsaid top wall undersurface portion engages said body top edge.

6. The sealing cap of claim 5 for a container body in which said skirt extends from said top edge along the outer surface of said body; wherein said second flange of said cap is outwardly of said first flange, said ridge projects laterally inward from said second flange, and said second flange has an exterior abutment providing a surface for engagement with pressure means to force said cap onto said body and said latching surfaces in snap-lock dogging engagement.

7. A tightly sealed flexible container of paperboard or the like comprising a container body having a top edge about its mouth and a side wall of uniform thickness, and

9. an integrally downwardly folded skirt of uniform thickness hingedly extending from said top edge in flush engagement with and along said side Wall of said body and terminating in a shoulder having a latching surface extending laterally with respect to said side wall, said skirt and side wall having a combined unifonn thickness throughout; and a cap comprising a top wall overlying said mouth and engaging said top edge, a flange depending from said top, and a ridge projecting laterally from said flange and having a latching surface in interlocking engagement with said latching surface of said container body, the distance between said cap latching surface and said top edge being such compared to the distance between said container body latching surface and said top edge as to stress said cap flange and maintain said latching surfaces interlocked.

8. A tightly sealed flexible container of paperboard or the like comprising a container body having a top edge about its mouth and a side wall of uniform thickness, and an integrally downwardly folded skirt of uniform thickness hingedly extending from said top edge in flush engagement with and along said side wall of said body and terminating in a shoulder having a latching surface extending laterally with respect to said side wall, said skirt and said side wall having a combined uniform thickness throughout; and a cap of a relatively stiff elastic plastic material capable of restoration to its original shape after flexing thereof and comprising a top wall overlying said mouth and engaging said top edge, a pair of spaced flanges depending from said top wall adjacent the periphery thereof which with an undersurface portion of said top wall therebetween define a groove gripping the side wall and skirt of said container body at said mouth with a first of said flanges in tight flush engagement wtih said side Wall and a second of said flanges in tight flush engagement with said skirt, and a ridge projecting laterally from said second flange and having a latching surface in engagement with said container body latching surface, the distance between said latching surface on said cap and the undersurface portion of said top wall in engagement with said body top edge being such compared to the distance between said top edge and said container body latching surface as to effect tensile stress in said cap flange to provide a tight interlock between said latching surfaces and a tight seal between said flange and said skirt.

9. A tightly sealed flexible container of paperboard or the like comprising a container body having a top edge about its mouth and a side wall of uniform thickness, and an integrally downwardly folded skirt of uniform thickness hingedly extending from said top edge in flush engagement with and along said side wall of said body and terminating in a shoulder having a latching surface extending laterally with respect to said side wall, said skirt and said side wall having a combined uniform thickness throughout; and a cap of a relatively stiff elastic material capable of restoration to its original shape and comprising a top wall overlying said mouth and engaging said '10 top edge, and a pair of spaced flanges depending from said top wall adjacent the periphery thereof which with an undersurface portion of said top wall therebetween define a groove gripping the side wall with a first of said flanges in tight flush engagement with said side wall and a second of said flanges in tight flush engagement with said skirt, said second flange being longer than said first flange and having a ridge projecting laterally therefrom having a latching surface in engagement with said cont-ainer body latching surface, the distance between said cap latching surface and said top edge being such compared to the distance between said container body latching surface and said top edge as to maintain said latching surfaces interlocked, and the portion of said cap top wall inward of the inner one of said first and second flanges being recessed to form a stiffening wall bearing against said inner flange to maintain said flange in tight engagement with said container body.

10. A flexible container body of paperboard or the like, and a closure cap therefor providing a tightly sealed interlock with said body when the cap is applied thereto; the container body comprising an edge about its mouth, a flexible side wall of uniform thickness, and a skirt of uniform thickness integral with and hingedly connected to said body edge folded along said side wall providing with said side wall two separate plies, said skirt terminating in a shoulder having a latching surface extending laterally with respect to said side wall; the cap being of relatively stiff elastic material capable of restoration to its original shape after flexing thereof and comprising a top wall for overlying said mouth and engageable with said container body edge, a flange depending from said top wall, and a ridge projecting laterally from said flange and having a latching surface for interlocking engagement with said latching surface of said container body; the distance between said cap latching surface and an undersurface portion of said cap top wall over said container body edge being such compared to the distance between said container body latching surface and said edge as to stress said cap flange and maintain said latching surfaces interlocked.

11. The structure of claim 10 wherein the skirt extends substantially completely around the container body wall.

12. The structure of claim 11 wherein the skirt is inside the container body and is provided with notches in its edge to facilitate folding of the skirt.

References Cited by the Examiner UNITED STATES PATENTS 2,740,444 4/ 1956 Martinelli 220- FOREIGN PATENTS 1,098,217 7/1955 France.

LOUIS G. MANCENE, Primary Examiner.

THERON E. CONDON, JAMES B. MARBERT,

Examiners. 

1. A SEALING CAP FOR A FLEXIBLE CONTAINER BODY OF PAPERBOARD OR THE LIKE WHICH HAS A TOP EDGE ABOUT ITS MOUTH, AND AN INTEGRALLY DOWNWARDLY FOLDED SKIRT OF UNIFORM THICKNESS THROUGHOUT HINGEDLY DEPENDING FROM SAID TOP EDGE ALONGSIDE THE SIDE WALL OF SAID CONTAINER BODY AND TERMINATING IN A SHOULDER HAVING A LATCHING SURFACE EXTENDING LATERALLY WITH RESPECT TO SAID SIDE WALL; SAID CAP BEING OF RELATIVELY STIFF ELASTIC PLASTIC MATERIAL CAPABLE OF RESTORATION TO ITS ORIGINAL SHAPE AFTER FLEXING THEREOF AND COMPRISING A TOP WALL FOR OVERLYING SAID MOUTH AND FOR ENGAGING SAID TOP EDGE, A PAIR OF SPACED FLANGES DEPENDING FROM SAID TOP WALL ADJACENT THE PERIPHERY THEREOF WHICH WITH AN UNDERSURFACE PORTION OF SAID TOP WALL THEREBETWEEN DEFINE AN OPEN BOTTOM GROOVE FOR GRIPPING THE SIDE WALL AND THE SKIRT OF SAID CONTAINER BODY AT SAID MOUTH WITH A FIRST OF SAID FLANGES IN TIGHT FLUSH ENGAGEMENT WITH SAID SIDE WALL, AND A SECOND OF SAID FLANGES IN TIGHT FLUSH ENGAGEMENT WITH SAID SKIRT, AND A RIDGE PROJECTING LATERALLY FROM SAID SECOND FLANGE AND HAVING A LATCHING SURFACE FOR DOGGING ENGAGEMENT WITH SAID LATCHING SURFACE OF SAID SKIRT, THE DISTANCE BETWEEN SAID LATCHING SURFACE ON SAID CAP AND SAID CAP UNDERSURFACE PORTION BEING SUCH COMPARED TO THE DISTANCE BETWEEN SAID BODY TOP EDGE AND SAID CONTAINER BODY LATCHING SURFACE AS TO EFFECT TIGHT DOGGING ENGAGEMENT BETWEEN SAID BODY AND CAP LATCHING SURFACES WHEN SAID CAP IS SEALED ON SAID BODY AND SAID TOP WALL UNDERSURFACE PORTION ENGAGES SAID BODY TOP EDGE. 